Color filter used in thin film transistor liquid displayer (TFT LCD) is a key component in conventional liquid displayers (LCDs), which can be used in the LCD for displaying the images in colors. The color filter mainly serves for transferring white light into three primary color lights, i.e. red (R), green (G), and blue (B) lights to display a full-color image on the displayer.
The production of the pattern layer of the color filter mainly comprises the following steps: uniformly coating a photo resist on a substrate by spin-coating method; removing solvent contained in the photo resist by pre-baking; selectively exposing the substrate at the area where is to be cured through a mask; developing the exposed substrate with an alkali solution; and then heating the substrate to cure the photo resist. Such steps are repeated three times to form red, green, and blue colors on the substrate sequentially.
In current color LCDs, they mainly use glass substrate as the substrate, which encounters problems of easily breaking and thick and heavy. To solve these problems, many efforts have made to develop new material suitable for producing flexible displayers to achieve purposes of lighting, not easily breaking, portable and flexible. In Japan Patent Publication No. Hei 11-271736, it disclosed a displayer with using a plastic substrate as the substrate. However, such a plastic substrate still encounters a problem of not being processed at an elevated temperature. Moreover, in Japan Patent Publication No. 2000-214468, it mentioned a low-temperature process for processing a plastic substrate.
Under the above environments, the present inventors have conducted an investigation to develop radiation curable and developable polyurethane and a radiation curable and developable composition, which can be applied to both glass and plastic substrates, and are suitable for both high-temperature process for glass substrate and low-temperature process for plastic glass to produce color filter, and thus completed the present invention.